Munich police cited the potential for "evidence suppression" as the reason for his arrest, just a week after he was added to a list of around 20 Volkswagen Group executives being investigated for fraud in relation to the diesel emissions cheating scandal.

"As part of an investigation into diesel affairs and Audi engines, the Munich prosecutor's office executed an arrest warrant against Professor Rupert Stadler on June 18," the Munich prosecutor's office said in a statement.

A judge ordered he be kept in detention, to reduce his risk of damaging the investigation.

German media chatter, quoted by Greg Kable on Twitter, has suggested the prosecutor suspected Stadler was preparing to meet – and potentially collude – with other Audi executives implicated in the Dieselgate scandal when he was arrested.

He was detained just hours before a Volkswagen supervisory board meeting in Wolfsburg, called so lawyers could present information about the investigation into Audi employees and their role in Dieselgate.

Audi used a statement to confirm its CEO has been "provisionally arrested", and highlighted the fact he's innocent until proven guilty – which he hasn't been, at this point.